Corrosion inhibiting composition



2,828,259 CORROSION mnmrr nso C MPOSITION Arthur F. Wirtel, Glendale, and Charles M. Blair, Jr.,

Webster Groves, Mm, assigiiors to IfetrOlite corpora tion, Wilmington, Del., a corporation "of Delaware No Drawing. Application April 8, 1953 er a Noam,

warms. (Cl-2 1535 surfaces of the metals. The invention is of particular value in the prevention of corrosion of pipe orequipment which is in contact with corrosive oil-containing media as, for example, in oil Wells producing corrosive oil or oil-brine mixtures, in oil refineries, and the like, but it is useful in numerous other systems or applications, as. the new compositions appearto possess properties which impart to metals resistance to attack by a variety of corrosive agents, such as brines, weak inorganic acids, Organic acids, CO H 8, etc. It is known that amines characterized by the presence of a basic nitrogen atom and one or more hydrocarbon groups having 8to 32 carbon atoms have corrosioninhibiting properties, and a large number of"th 'er"n" have been suggested for use as corrosion inhibitors, particularly for use in oil and gas wells, oil refineries and the like. "Such compounds have a moderately strong nitrogeri-containing basic group (either free or in 'saltform) which may be present as part of a heterocyclic ring structure, as in certain pyrrolinedione, pyridine or piperidine compounds, or not, as in abietyl or oleyl amine.

The present invention is based upon the discovery that 'the anticorrosive action of such agents, as a class, is markedly enhanced if they are associated with an alkylated aromatic sulfonic acid of the type hereinafter defined, or a salt thereof. We have no explanation'of this observed result, as in our tests, we have not found that the alkylated aromatic sulfonic acids which we use, or their salts,have any marked corrosion inhibiting action. On the other hand, we have found corrosion inhibitors, which when used conventionally reduce corrosion substantially, have their corrosion inhibiting action markedly enhanced by admixture with about 50% of an alkylated aromatic sulfonic acid salt.

Thus, the new compositions of the invention consist of admixtures of (1) a corrosion-inhibiting agent characterized by having a basic nitrogenatom, which may be an amino group or form a portion of a heterocyclic ring structure and at least one hydrocarbon group having 8 to 32 carbon atoms, with (2) analkylated aromatic sulfonic acid, which may be represented by the formula in which R is an alkyl radical having 3 to 12 carbon atoms, n is a number from 1w 3, and with therequirement that the total number of carbon atoms present in (R),, is at least 6, or the formula ice in which n is one or two, R is an alkyl group having 3 to 18 carbomatoms and with the requirementthat' the total number of carbon atoms in (R),,'is at least 9;

The nature of the cation does not seem to beof particular consequence. It can be hydrogen,'sodium, potassium, ammonium, the cation of a water-soluble amine, suchas monoethanol amine, diethanol amine, Ortriethanolf amine, or the cation Of a water-insoluble amine, such" as amyl amine, cyclohexyl amine, benzyl amine,fa'rnine's" derived from higher fatty acids having 8 to'l 8 carbon atoms, such as lauryl amine or'the'mixedamines derived from fats or Oils, which are cornmerciallyavailable'; or other cation, including polyamines or the like, such as ethylenediamine, in which case the polybasic ion can be combined with One or more sulfonic acid groups up to a number equal to' its" number of basic gr oupg'ei g., in the case of ethylene diamine, either one Or two moles; or some intermediate amount, of sulfonic acid p'er mole of diamine. If the cation is hydrogen it is possible that this agent may form salts with the corrosiondrihibiting amine, but inmost instances, we think that the corrosioninhibiting amine'and the sulfonic' acid Or sulfonate will: be present in simple admixture, as the corrosion inhibiting'arnine will generally, and advantageously, be used in 'the'form of a salt, 'as'will the sulfonic acid. Inaddition to these two essential constituents of the new compositionsfthere will normally be present addi tional conventional materials, such as solvents where the admixtures are to be used in liquid form, 'waxes orothei solidifying agents where the products are to be usedin solidstick form, and Waxes or other solidifying agents and a weighting material, such'as barium smote-0r lead oxide, where the compositidnsare to beused'inthe i'oirn of weighted sticksf The use of co rrosioninhibitors, particularly for oil and' gas well treatment, indiqu id form, or in stick form with or without weighting agents, is conye ntional an'dwell known, and the pre s'entinvei tion is concerned, not with the form of application o f the compositions, but witli'the enhancement of the cor-' rosion inhibiting 'a'ctionof the nitrOgen-c ontainingiagent by associationtherewith of thespecified alkylated aro matic sulfonic acidI' 1 In'general, we have found that minor proportions oi the; alkylated' aromatic sulfonic acid based On thel'corro sion inhibiting compound "are adequate to produce marked enhancement of the activity of the compositi ti; Thus, l0%' or le's'sof an alkylated aromatic sulfonic acid, based on the inhibitor, produces a marked effect. At present, we are not aware of" any requirement as to an; upper limit. 'It, so far as we are aware, will be fixed byeconomic considerations, as use of an excessofian" alkyla'ted aromatic sulfonic' acid does. not reduce the enhancement of the anticorrosion activity, nor do amounts in excess of 5 0 to based on the qorro sion inhibitor, appear to increase the enhancement be c 7 I At worst, an. excess serves as an additional diluent. Thus, therangefi yond that obtained with '10 to 5.0%.

we contemplate is from about 5% to about 100% of the alkyla'ted aromatic sulfonic acid, based nthecorf rosion inhibitor, but it is to be understood that'use "of larger amounts does not involve departure f romthe inventioul" As previously stated, the corrosion inhibitors used in atented, Mar. 35.: 25%

use in preparing the compositions of the invention are the N-aliphatic pyrrolinediones described in Patent 2,466,530, April 5, 1949, Blair and Gross. Typical useful inhibitors of this type which may be used in preparing the compositions of the present invention are:

N-octadecyl chloromaleimide; N-hexadecyl citraconimide; N-octadecylenemaleimide; N-laurylmaleimide; N-octylmaleimide;

N-benzyl maleimide; N-naphthenylmaleimide; N-tetradecyl-citraconimide; N-2 ethylhexylcitraconimide; N-abietylcitraconimide; N-docosylchlormaleimide; N-oleylbromomaleimide.

Other corrosion inhibitors which are known, and which may be used in preparing the compositions of the invention, are the cycloaliphatic and terpene-derived amines such as abietylamine, commercial rosin amine, hydroabietylamine, and the oxyalkylated derivatives of such amines as are described, for example, in Patent 2,510,063, Bried; 2,564,753, Cox; 2,564,757, Glasebrook; and 2,564,758 and 2,564,759, Haggard; the amino esters derived from high molecular weight carboxylic acids and hydroxy alkyl amines, such as those described in Patent 2,520,356, Bishop, and 2,614,981, Lytle. The relatively simple long chain alkyl monoamines such as laurylamine, stearylamine, oleylamine and distearylamine and the amines corresponding to naphthenic acids and the acids obtained by the oxidation of petroleum oils, are known to have corrosion inhibiting properties, and their effectiveness is markedly enhanced when they are used as the corrosion inhibiting agents in the new compositions.

From the foregoing it will be noted that there are a number of compounds characterized by the presence of a basic nitrogen atom and a hydrocarbon group having 8 to 32 carbon atoms which have corrosion inhibiting properties, and which have their effectiveness substantially increased by association with an alkylated aromatic sulfonic acid of the type described above. The effectiveness of the corrosion inhibitors varies, some being considerably more effective than others, and so far as we are aware, there will be variation in effectiveness of the compositions of the invention more or less parallel to the variations in effectiveness of the corrosion inhibitors per so.

We have heretofore referred to the fact that the new compositions of the invention may be used in liquid form, usually with the use of an appropriate solvent such as a mixture of high boiling aromatic hydrocarbons and medium boiling paraffinic hydrocarbons or may be used in stick form with or without weighting agents. The use of corrosion inhibitors in stick form and in Weighted stick form, the purpose of providing them in such form, and the preparation of products in such form is well known. See, for example, Patents 2,599,384 and 2,599,385, June 3, 1952. The compositions of the present invention may be used as the corrosion inhibiting constituents of weighted solid stick inhibitors as described in these patents or of non-weighted solid stick inhibitors.

The invention will be further illustrated by the following specific examples in which typical compositions of the invention are described. In each of them, we have found that the corrosion inhibiting action of the corrosion inhibitor is markedly enhanced by the alkylated aromatic sulfonic acid associated with it. This enhancement is also found with the wide range of inhibitors described above and the examples are, therefore, given purely by way of illustration and not by way of limitation.

Example I lbs. of commercial oleyl amine dissolved in 150 76 Example ll 50 lbs. of ammonium diisobutyl naphthalene sulfonate were substituted for the ammonium diisopropyl naphthalene sulfonate of Example I.

Example III A solid stick corrosion inhibitor was prepared by casting the homogeneous melt resulting from the mixing of the following ingredients at IOU-120 C.:

Lbs.

Abietyl amine linoleate 50 Ammonium diisopropyl naphthalene su1fonate 10 Microcrystalline wax of 186 F. M. P 4O Oxidized microcrystalline wax of 185 F. M. P. and

60 saponification value 20 The solid product has a density a little below 1.0 at 25 C.

Example IV A solid stick type corrosion inhibitor of high density particularly useful in the treatment of distillate wells prepared by casting the melt resulting from mixing thoroughly the following ingredients at about 120 C.:

Lbs. Product of Example III 38 Powdered barium sulfate 62 The solid product had a density of about 2.0 and a softening point of about F.

Example V 50 lbs. of cyclohexylammonium dodecyl benzene sulfonate were substituted for the ammonium diisopropyl naphthalene sulfonate of Example I.

In the foregoing we have referred at length to the inhibitors which are used as being compounds having one basic nitrogen atom and at least one hydrocarbon group having 8 to 32 carbon atoms. It is to be understood that these compositions may be used in the form of the free bases, or in partially neutralized form or in completely neutralized form, and such pantial or complete neutralization may be by means of an inorganic acid, such as sulfuric acid, or an organic acid, such as acetic acid, gluconic acid, a higher fatty acid or any of the acids which are used for neutralizing basic amino corrosion inhibitors, in accordance with usual practice.

An additional advantage in the use of the new compositions which we have observed is a substantial and unexpected decrease in certain emulsification problems sometimes encountered. Thus, when corrosion inhibitors of the type used in the compositions of the invention in hydrocarbon-water systems where the hydrocarbon is relatively pure, i. e., in gasoline, kerosene, distillate, liquefied petroleum gases and the like, as contrasted with crude oil, there is a tendency for oil-in-water emulsions to form. This tendency is greatly reduced, or absent, when the new compositions are used. This is surprising, because the alkylated aromatic sulfonates, while known to resolve water-in-oil emulsions, have found no application as demulsifiers for oil-in-water emulsions.

We claim:

1. New corrosion inhibiting compositions consisting essentially of, as an active corrosion inhibiting constituent, a nitrogen-containing agent characterized by having only one nitrogen atom, which nitrogen atom is basic, and at least one hydrocarbon group having 8 to 32 carbon atoms and in admixture therewith, as an agent which enhances the corrosion inhibiting activity of the corrosion inhibiting constituent, at least 5% and not over 100%,

based on the corrosion inhibiting constituent, of an alkylated aromatic sulfonic acid compound selected from the class consisting of alkylated naphthalene sulfonic acid compounds of the formula (12).. o. cation in which R is an alkyl radical having 3 to 12 carbon atoms, n is a number [from 1 to 3, with the proviso that the total number of carbon atoms present in (R),, is at least 6, and alkylated benzene sulfonic acid compounds of the formula (3),. so. cation in which n is a number from 1 to 2, R is an alkyl group having 3 to 18 carbon atoms, with the proviso that the total number of carbon atoms, in (R),, is at least 9.

t 2. The process of inhibiting corrosion of ferrous metals exposed to chemically corrosive agents which includes exposing the metal to the action of a composition which contains, as an active corrosion inhibiting constituent, a

nitrogen-containing agent characterized by having only one nitrogen atom, which nitrogen atom is basic, and at least one hydrocarbon group having 8 to 32 carbon atoms and which contains, in admixture therewith, as an agent which enhances the corrosion inhibiting activity of the corrosion inhibiting constituent, at least and not over 6 100%, based on the corrosion inhibiting constituent, of an alkylated aromatic sulfonic acid compound selected from the class consisting of alkylalted naphthalene sulfonic acid compounds of the formula SO; cation in which R is an alkyl radical having 3 to 12 carbon atoms, n is a number from 1 to 3, with the proviso that the total number of carbon atoms present in (R),, is at least 6, and alkylated benzene sulfonic acid compounds of the formula M cation in which n is a number from 1 to 2, R is an alkyl group having 3 to 18 carbon atoms, with the proviso that the total number of carbon atoms in (R),, is at least 9.

References Cited in the file of this patent 

1. NEW CORRISION INHIBITING COMPOSITIONS CONSISTING ESSENTIALLY OF, AS AN ACTIVE CORROSION INHIBITING CONSTITUENT, A NITROGEN-CONTAINING AGENT CHARACTERIZED BY HAVING ONLY ONE NITROGEN ATOM, WHICH NITROGEN ATOM IS BASIC, AND AT LEAST ONE HYDROCARBON GROUP HAVING 8 TO 32 CARBON ATOMS AND IN ADMIXTURE THEREWITH, AS AN AGENT WHICH ENCHANCE THE CORRISON INHIBITING ACTIVILY OF THE CORRISON INHIBITING CONSTITUENT, AT LEAST 5% AND NOT OVER 100%, BASED ON THE CORRISON INHIBITING ACTIVITY OF THE CORRISON ATED AROMATIC SULFONIC ACID COMPOUND SELECTED FROM THE CLASS CONSISTING OF ALKYLATED NAPHTALENE SURFONIC ACID COMPOUNDS OF THE FORMULA FGI-01 IN WHICH R IS ALKYL RADICAL HAVING 3 TO 12 CARBON ATOMS, N IS A NUMBER FROM 1 TO 3, WITH THE PROVISO THAT THE TOTAL NUMBER OF CARBON ATOMS PRESENT IN (R)N IS AT LEAST 6, AND ALKYLATED BENZENE SULFONIC ACID COMPOUNDS OF THE FORMULA 